In addition to manufacturing processes such as a lithographic process, a film formation process, and an etching process, manufacture of a semiconductor device requires a measurement process of a micropattern created by the above processes for the improvement of yield.
Recently, to meet the needs for higher performance and higher functions in devices, the size of a pattern has been made minuter, and its two-dimensional and three-dimensional shapes have also been increasingly complex. In order to evaluate the pattern having the complex shapes, it is necessary to measure the sectional shape of the pattern, compared to conventional critical dimension (CD) measurement that only measures the CD of a particular part of the pattern section.
The use of scatterometry that utilizes light has recently been on the increase. The scatterometry is a technique in which light is applied to a measurement target pattern, and a pattern sectional shape corresponding to the spectral profile of the reflected light is estimated by referring to a library which depends on a pattern sectional shape previously constructed by a numerical calculation.
The advantages of the scatterometry include being a nondestructive measurement and being able to measure not only the CD but also, for example, the height and sidewall angle of the pattern.
On the other hand, the scatterometry requires the previous construction of the library, so that know-how is needed to construct a layer stack model from, for example, a sectional photograph of the pattern. In particular, a good library needs to be created to obtain accurate measurement results, for which considerable cost (labor and time for a skilled engineer) has been required.